Miniaturization within the computing industry has led to the success of portable computers. Laptop, or notebook, computers have become increasingly small in size and lightweight. However, even laptop computers have become too cumbersome for everyday portable computer access. Accordingly, portable digital assistants (PDAs) were introduced. PDAs provide computing functionality in a form factor sufficiently small that it is easy for a user to carry around.
Subsequent advancement of the wireless industry led to PDAs that provide wireless access to the telecommunication infrastructure. Accordingly, many of today's PDAs can facilitate both voice and data communication. The convergence of portable computing devices and telecommunication devices has led to a number of mobile devices that are available to consumers today. Such mobile devices include PDAs paging devices, smart phones and the like.
However, the drive to portability and a reduced form factor have introduced a number of limitations on the mobile devices. For example, mobile devices generally have limited room for a keyboard in order to provide a minimal size that affords portability.
Ideally, a mobile keyboard equivalent of full keyboard would be implemented on the mobile device. However, in order to achieve such a result, the keys would be too small to be practical. Accordingly, a number of trade-offs have been proposed and implemented by the mobile device industry.
Generally, the solutions assign multiple characters to character keys on a mobile keyboard. Each of the character keys is assigned a principal character, usually an alpha character. Modifier keys are provided so that a user can access other characters assigned to each key. Modifiers include keys such as a shift key, an alt key, a symbol key and the like. Such keyboards are well known in the art and are provided on portable digital assistants (PDAs), such as the BlackBerry® by Research in Motion or the Treo® by Palm, Inc., as well as a host of cellular phones and smart phones.
As a result of the keyboard layout it is often required to press multiple keys to obtain a single character. For example, many PDAs require the depression of a “number lock” modifier key in addition to the character key to represent a number. This can pose a particular annoyance when a user has to enter a password, for example, that is exclusively numeric.
This is particularly true for users who have implemented an additional layer of security. For example, passwords generated by a token, such as the RSA SecurID® token for example, may be required in addition to a PDA password. Such tokens typically generate quasi-random numbers used as an additional layer of security. Similarly, in some instances users may have to gain access to the PDA via a smart card. Accordingly, in addition to the PDA password, a smart card password is required. Frequently, such passwords are numeric. Devices such as tokens and smarts cards are well known in the art and will be referred to generically hereafter as authenticators.
Therefore, it is desirable to provide a method for increasing the ease of entering a string of characters that would normally required the depression of a modifier key in addition to the character key.